The present invention relates to a method of increasing the color stability and reducing the microbial counts of both oleoresin Capsicum and the residual cake from which the oleoresin has been extracted. The process simultaneously extracts and concentrates the principal flavor, aroma, color, and other active compounds of the genus Capsicum, produces a concentrated and standardized food-grade extract of active components, and a standardized food-grade residual solid, with both the extract and residual solids having improved resistance to color loss and having significantly reduced microbial counts.
Concentrated extracts of the genus Capsicum are universally used for flavoring and coloring of food, beverages, and pharmaceuticals. These extracts are traditionally used where a standardized, sterile, and uniform concentrate offers the benefits of control which are inherently difficult to obtain from raw spice, or where the bulk of the raw material is not needed or undesirable.
Ground Capsicum solids are universally used for flavoring, coloring, and imparting otherwise favorable characteristics to food and beverages where the bulk, functional characteristics, and appearance of the food or beverage is important.
Traditional extraction processes for the manufacture of concentrated extracts (concentrated several fold as compared with the raw material) involve not only the use of various non-edible solvent systems, but also a large proportion of solvent in relation to the compounds of interest. Many require the use of petroleum distillates, chlorinated solvents, or highly flammable solvents which must be eliminated almost completely from the finished products to make them safe for consumption. These systems require expensive distillation equipment and special precautions must be taken to ensure worker safety and to limit environmental impact. The intensive processing required often destroys, modifies, or loses some of the more unstable compounds, delicate aromas, flavors, or pigments. More significantly, the last traces of undesirable non-edible solvents are very difficult to separate from the concentrated extract. The residual solid must necessarily contain the same residual non-edible solvents, which are removed only with difficulty. Such residual solvents limit the potential use of the residual solid for human consumption, and are potential environmental contaminants.
Other concentration techniques rely on high pressure equipment to obtain good solvating properties from gases, e.g., liquid or supercritical CO.sub.2 (U.S. Pat. No. 4,490,398). High pressure liquefied or supercritical gas extraction requires expensive equipment and has limited solvating abilities for some compounds requiring the addition of co-solvents, or solvents such as propane and butane, which are also difficult to control and may be environmentally sensitive or undesirable in a finished product.
Following extraction and desolventization, the concentrated extract is often standardized with edible solvents and emulsifiers to provide a concentrate with reproducible levels of the active or principal compounds of interest to the user.
In an effort to overcome the shortcomings and risks associated with the above-mentioned processes, extraction has been carried out using edible solvents such as vegetable oils or lard. Typical extraction procedures are disclosed in U.S. Pat. Nos. 3,732,111; 2,571,867; and 2,571,948. These methods require a relatively large volume of solvent in relation to the compounds of interest and result in a dilute extract which is limited in its application and which has few of the advantages of the concentrates which can be produced using volatile solvents.
U.S. Pat. No. 4,681,769 discloses a method for simultaneously extracting and concentrating in a series of high pressure countercurrent mechanical presses using relatively small amounts of vegetable oil as the solvent in an attempt to overcome the problem of dilution inherent in earlier processes. This method suffers from severe limitations in temperature and pressure ranges in an attempt to avoid unacceptable oxidative damage, color loss, yield losses, and flavor changes with the final result being that contact times must be unduly extended for up to 16-24 hours, adding greatly to the cost of the process. Extraction cycle times are unduly long for a given size pressing operation, and the process does not provide for a controlled degree of browning or for sterilization of the extract or of the residual solid. It is also limited to temperatures of less than 100.degree. F. and thus it does not allow for the use of edible solvents which have a melting point of more than 100.degree. F. or which are highly viscous at temperatures of less than 100.degree. F. Maximum pressures of up to about 500 PSI (cone pressure) are claimed and this severely limits the efficiency and throughput rate for a given size pressing operation, as shown by the disclosure of this patent.
Traditional methods for the sterilization of ground spices, including Capsicum, involve the use of extremely toxic substances such as ethylene oxide or methyl bromide, irradiation, or steam and moisture treatment to reduce plate counts to less than 100,000. Chemical sterilization and irradiation of spices are disagreeable to the consumer because of the perceived risk of residual chemicals and/or radiation remaining in the plant matter and, as a result, several processes using added moisture, such as water or steam, at elevated pressures have been developed as alter-natives. Typical sterilization procedures are disclosed in U.S. Pat. Nos. 4,210,678, 4,790,995, and 4,910,027. All sterilization processes are inherently costly in that they require a separate processing step or steps to accomplish the sterilization, and also present the possibility of further degrading the more unstable components. Addition of moisture or water vapor, as disclosed in U.S. Pat. Nos. 4,210,678 and 4,910,027, prior to or during the heating and sterilization process results in a cooked aroma not typical of the fresh, dehydrated spice and also results in steam distillation and loss of some of the volatile flavor and aroma constituents.
U.S. Pat. Nos. 4,790,995 and 4,910,027 require the addition of a coating of animal protein to protect the spice from the loss of volatile aroma compounds during the sterilization process with water vapor. U.S. Pat. No. 4,210,678 requires bringing the moisture of the spice to above 8-14%, in some cases up to 16-20%, and holding the spice for an extended period of time prior to sterilization to equilibrate the moisture. This additional step is costly and time consuming. In the case of Capsicums, severe browning and off aromas and flavors are developed in the presence of moistures in excess of 8% at elevated temperatures above 180.degree. F.
Traditional methods for controlling the brownness or degree of caramelization of Capsicum solid to enhance its visual appearance involve the use of elevated temperatures and the addition of vegetable or animal fats or oils to bring up the surface color and luster of the ground spice. This requires a separate and costly processing operation.
Above all, there is the unsolved problem of obtaining satisfactory yields, quality, and throughput rates of acceptable extract having an acceptable content of active principle in the edible solvent without undesirable oxidative damage to, and reduced stability of, the principal compounds of interest, while at the same time providing for simultaneous sterilization of both the spice solid and extract.
Obviously, existing prior art procedures leave much to be desired, and it is a primary objective of the present invention to provide a procedure for the production of Capsicum products having enhanced color stability and which otherwise obviates the shortcomings of the prior art.